precision measurement of g e p /g m p with blast
DESCRIPTION
Precision Measurement of G E p /G M p with BLAST. Chris Crawford MIT Laboratory for Nuclear Science for the BLAST collaboration. Motivation. † Nucleon Electromagnetic Form Factors, Haiyan Gao, Int. J. of Mod. Phys. E, 12, No. 1, 1-40(Review) (2003). Form Factor Ratio @ BATES. - PowerPoint PPT PresentationTRANSCRIPT
Precision Measurement of GE
p/GMp with BLAST
Chris Crawford
MIT Laboratory for Nuclear Science
for the BLAST collaboration
Motivation
†Nucleon Electromagnetic Form Factors, Haiyan Gao, Int. J. of Mod. Phys. E, 12,
No. 1, 1-40(Review) (2003)
Form Factor Ratio @ BATES
New technique: polarized beam and target Exploits unique features of BLAST
» internal target: low dilution, fast spin reversal» large acceptance: simultaneous measurement of all Q2 points » symmetric detector: ratio measurement
Different systematics » insensitive to Pb and Pt
Q2 = 0.07 – 0.9 (GeV/c) 2 » overlap with JLab data
and RpEX (future exp.at Bates to measure rp)
Asymmetry Super-ratio Method
Polarized cross section
Super-ratio
Detector Package
BLAST Coils
Backward-Angle TOF
TOF Scintillators
Wire Chambers
Cerenkov Detectors
Neutron Detectors
LADS Detectors
BLAST
Wire Chamber Tracking
Garfield drift time simulation Newton-Rhapson track fitter
200μm resolution 20:1 signal to noise ratio
Preliminary Data
Theta Resolution
Beam AsymmetryYield
Projected Results
Statistics» A1, A2
Systematics
» θ*1, θ*
2
Δp, Δθ, Δβ
Errors are minimized as a function of β (target spin angle)
BLAST Collaboration
R. Alarcon, E. Geis, J. Prince, B. Tonguc, A. Young
Arizona State University
J. Althouse, C. D’Andrea, A. Goodhue, J. Pavel, T. Smith,
Dartmouth College
T. Akdogan, W. Bertozzi, T. Botto, M. Chtangeev, B. Clasie, C. Crawford, A. Degrush, K. Dow, M. Farkhondeh, W. Franklin, S. Gilad,
D. Hasell, E. Ilhoff, J. Kelsey, H. Kolster, A. Maschinot, J. Matthews, N. Meitanis,
R. Milner, R. Redwine, J. Seely, S.Sobczynski, C. Tschalaer, E. Tsentalovich,
W. Turchinetz, Y. Xiao, H. Xiang, C. Zhang, V. Ziskin, T. Zwart
Massachusetts Institute of TechnologyBates Linear Accelerator Center
D. Dutta, H. Gao, W. Xu
Duke University
J. Calarco, W. Hersman, M. Holtrop, O. Filoti, P. Karpius, A. Sindile, T. Lee
University of New Hampshire
J. Rapaport
Ohio University
K. McIlhany, A. Mosser
United States Naval Academy
J. F. J. van den Brand, H. J. Bulten, H. R. Poolman
Vrije Universitaet and NIKHEF
W. Haeberli, T. Wise
University of Wisconsin